From 90f9d70a582c02f50b4dd847166cd5b037219891 Mon Sep 17 00:00:00 2001 From: "bibo,mao" Date: Wed, 31 Jan 2007 17:50:31 +0800 Subject: [IA64] enable singlestep on system call As is pointed out in http://www.gelato.org/community/view_linear.php?id=1_1036&from=authors&value=Ian%20Wienand#1_1039, if single step on break instruction, the break fault has higher priority than the single-step trap. When the break fault handler is entered, it advances the IP by 1 instruction so break instruction single-stepping is skipped, actually it is next instruction which is single stepped. This patch modifies this, it adds TIF_SINGLESTEP bit for thread flags, and generate a fake sigtrap when single stepping break instruction. Test case in attachment can verify this. Any comments is welcome. Signed-off-by: bibo, mao Signed-off-by: Tony Luck --- arch/ia64/kernel/ptrace.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'arch/ia64/kernel') diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c index aa705e46b974..f1ec129ae3a1 100644 --- a/arch/ia64/kernel/ptrace.c +++ b/arch/ia64/kernel/ptrace.c @@ -1405,6 +1405,7 @@ ptrace_disable (struct task_struct *child) struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child)); /* make sure the single step/taken-branch trap bits are not set: */ + clear_tsk_thread_flag(child, TIF_SINGLESTEP); child_psr->ss = 0; child_psr->tb = 0; } @@ -1525,6 +1526,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data) * Make sure the single step/taken-branch trap bits * are not set: */ + clear_tsk_thread_flag(child, TIF_SINGLESTEP); ia64_psr(pt)->ss = 0; ia64_psr(pt)->tb = 0; @@ -1556,6 +1558,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data) goto out_tsk; clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + set_tsk_thread_flag(child, TIF_SINGLESTEP); if (request == PTRACE_SINGLESTEP) { ia64_psr(pt)->ss = 1; } else { @@ -1595,13 +1598,9 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data) } -void +static void syscall_trace (void) { - if (!test_thread_flag(TIF_SYSCALL_TRACE)) - return; - if (!(current->ptrace & PT_PTRACED)) - return; /* * The 0x80 provides a way for the tracing parent to * distinguish between a syscall stop and SIGTRAP delivery. @@ -1664,7 +1663,8 @@ syscall_trace_leave (long arg0, long arg1, long arg2, long arg3, audit_syscall_exit(success, result); } - if (test_thread_flag(TIF_SYSCALL_TRACE) + if ((test_thread_flag(TIF_SYSCALL_TRACE) + || test_thread_flag(TIF_SINGLESTEP)) && (current->ptrace & PT_PTRACED)) syscall_trace(); } -- cgit v1.2.2